The present invention concerns a device for locking the door of a domestic electrical appliance, such as the door of a front- or top-loading washing machine, or the door of a dishwashing machine.
More specifically, the object of the invention is a locking and unlocking device including:
a housing having an aperture for the introduction of an engagement member fixed to the door; PA1 a retainer member mounted movably in the housing, which member is movable between a working position in which it retains the said engagement member when the door is closed and enables the domestic electrical appliance to operate, and a rest position in which it allows the said engagement member to be released when the door is opened and the engagement member to enter the said aperture when the door is closed; and PA1 an electromechanical control device comprising a movable locking member which is movable, under predetermined conditions, to a locking position in which it stops the aforesaid retainer member moving from the work position to the rest position.
In many domestic electrical appliances, safety standards require that the loading door of the appliance cannot be opened under certain conditions. For example, it must not be possible to open the loading door of a washing machine or a washer-dryer while the laundry-carrying drum is moving and/or when the level of water in the washing chamber exceeds a predetermined level.
In order to comply with these standards, door locking and unlocking devices of the type defined above are widely used, which include electrically controlled actuators such as solenoids or actuators having thermocouples and heating resistors. These safety devices prevent the door being opened during a washing cycle.
However, the currently available locking and unlocking devices cannot prevent the domestic electrical appliance from being started deliberately by the user while the door is open. In fact, in the case of a device of the type defined above, it is possible manually to move (possibly using an object or simple tool) the retainer member from the rest position to the working position while the door is open and, in these conditions, to start the appliance. This can obviously be dangerous.
The object of the present invention is to provide a locking and unlocking device for the door of a domestic electrical appliance, which makes it impossible, or at least extremely difficult, for such improper and, consequently, dangerous, use to occur.
This and other objects are achieved according to the invention by a locking and unlocking device for the door of a domestic electrical appliance including a housing with an aperture into which an engagement member mounted on the door is introduced, a retainer member mounted movably in the housing and movable between a working position in which it retains the engagement member when the door is closed and enables the domestic electrical appliance to operate, and a rest position in which it allows the engagement member to enter the aperture when the door is closed, an electromechanical control device including a movable locking element which is movable under predetermined conditions, to an obstruction position in which it stops the retainer member moving from the working position to the rest position, and stop means which lock the retainer member in the rest position when the door is open and which release the retainer member on closing the door.